Pharmacology · Class
Aminosalicylates (5-ASA) !
Anti-inflammatory medicines that deliver 5-aminosalicylic acid to the inflamed bowel. A base treatment for mild to moderate ulcerative colitis.
Updated 2026-11-01
What they are
Medicines built around 5-aminosalicylic acid (5-ASA, mesalazine), which acts topically on the bowel lining. Azo compounds (sulfasalazine, olsalazine, balsalazide) release 5-ASA when colonic bacteria split the azo bond; mesalazine formulations release it by pH or time.
Mechanism of action
5-ASA works on the mucosa rather than through the bloodstream. It dampens mediators from the cyclooxygenase and lipoxygenase pathways, interferes with inflammatory cytokines (including NF-κB activity) and scavenges reactive oxygen species. The exact mechanism is not fully known.
Target: Colonic mucosa (local anti-inflammatory action of 5-ASA)
Drugs in this class
- SulfasalazineA pro-drug that colonic bacteria split into 5-ASA, which calms the colon, and sulfapyridine. Used in ulcerative…Colonic mucosa (5-ASA) and immune cells (anti-inflammatory and immunomodulatory effects)
- Mesalazine5-aminosalicylic acid packaged to reach the inflamed bowel. It calms the lining locally and is a base treatment for…Colonic mucosa (local anti-inflammatory action)
Others in the class
- Olsalazine
- Balsalazide
Test yourself
Think of the answer, then tap the question to see it.
Which part of sulfasalazine is the active anti-inflammatory one in ulcerative colitis?
5-aminosalicylic acid (5-ASA); sulfapyridine is mainly the carrier and causes most adverse effects.
What frees 5-ASA from sulfasalazine in the colon?
Bacterial azoreductases that split the azo bond.
Which kidney complication is linked to 5-ASA drugs?
Interstitial nephritis and, rarely, kidney failure; kidney function is checked before and during treatment.
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); DailyMed - MESALAMINE tablet, delayed release (DailyMed (U.S. National Library of Medicine), 2026); DailyMed - SULFASALAZINE tablet, delayed release (DailyMed (U.S. National Library of Medicine), 2026); Farmacología básica y clínica (Katzung), 16.ª ed., cap. 62 (McGraw Hill, 2025).
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Representative model, for educational purposes only.